#app {
  width: 100px;
  height: 100px;
  background-color: #ddd;
  border: 1px solid black;
}

.container h1,
.container h2,
.container h3 {
  margin-bottom: .8em;
}

nav {
  border: 1px solid black;
  left: 0px;
  right: 0px;
}
